Vehicle headlamp with internal air-exchange feature

摘要

The headlamp unit has an air extract hole (19) under the front of the lens and an air inlet hole (21) in the bottom of the housing behind the reflector. Air is drawn out of the outlet hole by the negative pressure under the front of the headlamp when the vehicle is moving. Fresh air is drawn into the rear of the housing and rises over the rear of the reflector and down the inside surface of the lens to a duct (220 which leads to the extract hole. Any dust and dirt in the inlet air is deposited behind the reflector leaving clean air to flow over the front of the reflector and over the inside of the lens. The extraction of air can be enhanced by an air duct at the outlet hole to draw air out of the headlamp by a venturi pumping process.